Described below as an example of a conventional power converting apparatus is a converter capable of regeneration control operation.
A power converting apparatus is configured with AC sides of single-phase sub-converters having a DC voltage lower than a DC voltage of a three-phase main converter connected in series with AC input lines of individual phases of the main converter. The power converting apparatus is controlled by driving the main converter by gate pulses generated at a rate of one pulse per half cycle so that a voltage generated at an AC terminal of each sub-converter becomes equal to the difference between an AC power supply voltage and a voltage generated at each AC terminal of the main converter. This arrangement makes it possible to suppress harmonics without use of a reactor having a large capacity and reduce power loss and electromagnetic noise (refer to Patent Document 1, for example).